The proportioning valve mounted below where the master cylinder is mounted.

The stock brakes on a CJ-2A are frightening by modern day standards. They
use a single cylinder master cylinder that has no redundancy and small
drums all around. I wanted to have a dual cylinder master cylinder and
disk brakes up front. I also wanted power brakes because I was planning on
running an automatic transmission.

Pedal

The first step in the brake swap was to convert to a swing arm brake pedal.
The stock CJ-2A uses a pedal through the floor and the pedal is mounted to
the frame rail. Pedals that are mounted through the floor can bind up if
the frame and body get twisted up, I didn't want this. I bought a swing
arm brake pedal from a CJ-7 with an automatic transmission. I wanted the
donor to have an automatic transmission so that I would get the wider pedal
making it less likely that my foot would slip off the pedal.

It turned out that the distance from the firewall to the dash on a CJ-2A is less
than the distance on a CJ-7, so I had to shorten and modify the part of the
pedal swing that mounts to the dash. Engine clearance and clearance from the
gas pedal forced me to mount the swing arm to the left of the steering column.
When there was clearance for the master cylinder and booster, the pedal itself
was too long, at the wrong angle, and too far left. I cut the pedal and welded
it back together with a piece of 2x2 square tubing to readjust the pedal angle
and length. I wanted to be sure that I could get a full throw on the pedal
in case I needed a full throw to stop. This puts the pedal in a pretty
awkward place, but I have gotten used to it.

On the dash side of the swing arm pedal, I shorten the swing and drilled some
holes through it. To attach it to the dash, I welded a piece of angle iron
to the back of the dash with some holes through it. The pedal swing is bolted
to the firewall and to the bracket welded to the back of the dash. This keeps
it very securely attached.

Master Cylinder

The master cylinder and power brake booster needed a flat surface to mount to
that would clear the engine and hood. I placed it about as close to the hood
as I could and in the end, it doesn't rub at all. I bought the master cylinder
and power brake booster from a CJ-7 thinking this would make it easier to use
it with my swing arm pedal. I was kind of wrong on that.

The CJ-7 uses a bracket to relocate the power brake booster and I could not
use the bracket. The other complication was the bolt pattern on the two sides
of the bracket were different. I welded up the old holes in the pedal swing
and redrilled it for the booster bolt pattern. Next, I took the push rod
from the swing and the push rod from the relocation bracket. I cut the two
push rods and welded them back together to get the two halves that I needed.

The Buick 231 V6 came from a donor that had power brakes, so it was a simple
matter of hooking up the vacuum hose to the booster. I ran brake lines from
the master cylinder to the proportioning valve which was pretty tight on the
hood, but it clears.

Proportioning Valve

The proportioning valve is actually from a late 70s Scout II. It was
just a vehicle I was parting out and it had a nice proportioning valve. The
Scout II drum cylinders and calipers are about the same size as the ones
I was using on the CJ-2A. I mounted the proportioning valve just below the
master cylinder to keep it out of the way. Since the brake lines from the
proportioning valve go to the frame rail, I put a spring shaped loop in both
lines to absorb flex between the body and the frame.

Disks and Drums

When Pieces and Parts was finally ready to hit the trail, it had drums in
the back from a '78 Cherokee and disks up front from the same vehicle. The
drums are big 11"x2" drums which are much larger than stock. I
didn't see the need to go with disks in the back, the drums have been fine
and they are a lot less expensive. The disks up front use the large calipers
and fat rotors found on late 70s Cherokees. The stopping power is excellent
for such a light vehicle.

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